The present invention relates to a paging system and, more particularly, to a paging system in which a mobile or on-board radio unit of a vehicle telephone for business use may function as a repeater as needed.
As is well known in the art, a vehicle telephone for business use includes a central radio station and mobile radio units which are individually mounted on vehicles. The central station transmits a particular call signal to a desired one of the mobile units over a radio channel and, thereafter, a communication is held between the two remote stations. When a call from the central station is received by the mobile unit while a person who is expected to operate the vehicle is away from the vehicle, a call lamp provided on the mobile unit is turned on to allow the person to see the call and, then, take any necessary action when he or she returns to the vehicle.
On the other hand, a paging system is implemented with a central radio station and portable receivers which may individually receive call signals from the central station. Any of the receivers which has received a call signal and determined that the call is meant therefor drives a speaker or the like to alert a user of the receiver to the call by an audible connect tone. Some of the modern paging systems proposed are capable of transferring even voice messages to the users of such portable receivers.
Assuming a salesman who is engaged in sales activities aided by a vehicle on which a telephone for business use is mounted, connection may eventually be established between the central radio station and the salesman even if the salesman is away from the vehicle. However, this is unachievable unless the salesman returns to the vehicle and, therefore, lacks in rapidity or directness. An implementation which may be contemplated to solve such a problem is providing the salesman with a portable receiver of a paging system. This implementation, however, brings about another problem that a call cannot be perceived by the salesman without needing two consecutive and troublesome steps, i.e., calling up the salesman who is expected to be in the vehicle by a vehicle telephone procedure and, if the salesman is absent in the vehicle, calling him or her up again by a paging procedure which is different from the vehicle telephone procedure.